Ion implantation gas supply system

ABSTRACT

The present disclosure describes a system and a method for providing a mixed gas to an ion implantation tool. The system includes a water supply, an electrical source, a gas generator. The gas generator is configured to generate a first gas from the water supply and the electrical source. The system also includes a first flow controller configured to control a first flow rate of the first gas, a gas container to provide a second gas, a second flow controller configured to control a second flow rate of the second gas, and a gas pipe configured to mix the first and second gases into a mixed gas. The mixed gas can be delivered to, for example, an ion source head of the ion implantation tool.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 16/442,088, filed on Jun. 14, 2019, titled “IonImplantation Gas Supply System,” which is incorporated herein byreference in its entirety.

BACKGROUND

Ion implantation (IMP) is widely used in semiconductor fabrication forcreating regions of various dopant concentrations/levels. In an IMPprocess, ions are accelerated to bombard a solid target (e.g., substrateor film), thereby changing the properties (e.g., physical, chemical,and/or electrical properties) of the target. For example, in acomplementary metal-oxide semiconductor (CMOS) device, regions ofdifferent dopant concentrations can be formed by IMP. A gas supplysystem of an IMP tool provides the gas sources for the ions.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the common practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofillustration and discussion.

FIG. 1 illustrates an ion implantation apparatus with a gas supplysystem, according to some embodiments of the present disclosure.

FIG. 2 illustrates a gas supply system with a gas generator for an ionimplantation apparatus, according to some embodiments of the presentdisclosure.

FIG. 3 illustrates a clean gas generator for a gas supply system,according to some embodiments of the present disclosure.

FIG. 4 illustrates a method for providing a mixed gas for an ionimplantation apparatus, according to some embodiments of the presentdisclosure.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature on a second feature in the description that followsmay include embodiments in which the first and second features areformed in direct contact, and may also include embodiments in whichadditional features may be formed that are between the first and secondfeatures, such that the first and second features are not in directcontact. In addition, the present disclosure may repeat referencenumerals and/or letters in the various examples. This repetition doesnot in itself dictate a relationship between the various embodimentsand/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper,” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

The term “substantially” as used herein indicates the value of a givenquantity that can vary based on a particular technology node associatedwith the subject semiconductor device. In some embodiments, based on theparticular technology node, the term “substantially” can indicate avalue of a given quantity that varies within, for example, ±5% of atarget (or intended) value.

The term “about” as used herein indicates the value of a given quantitythat can vary based on a particular technology node associated with thesubject semiconductor device. In some embodiments, based on theparticular technology node, the term “about” can indicate a value of agiven quantity that varies within, for example, 5-30% of the value(e.g., ±5%, ±10%, ±20%, or ±30% of the value).

Ion implantation is widely used in semiconductor fabrication to formregions doped with desired ions (in a device or structure) to alter thechemical, physical, and/or electrical properties of the regions. An ionimplantation (“IMP”) system is a semiconductor fabrication apparatusused to implant one or more dopant elements into a semiconductor waferto form doped regions at desired depths in the semiconductor wafer. Thedopant elements are introduced into the semiconductor wafer with an ionbeam generated and controlled by the IMP. To produce the ion beam, animplant gas or feed material with the desired dopant material isintroduced into an ion source, where a high energy is applied to ionizethe gas or feed material to form the ion beam. An accelerating electricfield is provided by IMP electrodes to extract and direct the ion beammoving toward the semiconductor wafer.

In an IMP process, accelerated ions impinge a region of the substrate ofthe semiconductor wafer so these ions can be implanted into thesubstrate as dopants at desired locations/depths. These dopants canenable the device or structure to have desired properties, which areessential for various applications. For example, source and drainregions of a CMOS device are doped with dopants that have an oppositepolarity than the substrate and allow the CMOS device to be turned onand off with a gate voltage. The source and drain regions can be formedby performing IMPs on the substrate.

In the IMP process, ions can be accelerated to impinge the semiconductorwafer from various directions, depending on, e.g., the shape and thedepth of the doped region. For example, ions can be implanted into thesemiconductor wafer at a title angle and a suitable energy so the ionscan be implanted within a desired depth/location range. The tilt anglerefers to the angle between the direction of the ions and the surfacenorm of the semiconductor wafer. The tilt angle can be, e.g., about 0degrees to about 15 degrees. The IMP process can form regions doped withthe implanted ions (e.g., dopants). Ideal/theoretical values ofparameters, such as ion species, ion energy, ion dosage, and tilt angle,can be provided in a process recipe for the IMP process. Theseparameters can be used to determine the trajectory of ions when the ionsare doped into the semiconductor wafer and to determine the theoretical(e.g., ideal or desired) doping profile (e.g., the point-to-point dopantconcentration in the substrate) of the dopants. The dopants can bedistributed within a desired depth range into the top surface of thesubstrate.

Various factors (e.g., atom arrangement, ion species, ion energy, and/orequipment error) can cause the doped ions to change trajectory and theactual doping profile to deviate from the theoretical doping profile.For example, for some atom arrangements, when the actual tilt angle isless than the theoretical tilt angle, ions can be less susceptible tocollide with atoms of the substrate and can be implanted deeper into thesubstrate. Accordingly, the doped region can be more susceptible to achanneling effect, which involves ions penetrating through thesubstrate/doped region. The channeling effect can cause damage to thedoped region or the substrate, thus causing low yield of the fabricateddevice/structure. For some atom arrangements, when the actual titleangle is greater than the theoretical tilt angle, ions are moresusceptible to collide with the atoms of the substrate, causing the ionsto be ejected from the substrate. As a result, deviation from thetheoretical tilt angle can cause a doping profile different than thetheoretical doping profile.

During an IMP process, clean gas ions can also be mixed with theimplanting ions to remove by-product coating. For example, a borontrifluoride (BF₃) gas can be used to implant boron into certainsubstrate regions of the semiconductor wafer. However, the ion sourcechamber is usually constructed of a different metal (e.g., tungsten (W))than the implant gas. And the ionized BF₃ implant gas can react with thechamber's metal (e.g., W) to form byproducts (e.g., tungstenhexafluoride (WF₆)). The substrate can be exposed to the byproducts,thus degrading device performance. To mitigate the device degradation, aclean gas (e.g., xenon dihydride (XeH₂)) can be mixed with the implantgas (e.g., BF₃) to generate ionized hydrogen, which is used to removethe byproducts (e.g., WF₆).

The implant gas supply and clean gas supply for the ion implanter can beprovided by a gas supply system. The gas supply system can use gascontainers to supply the gases. These gas containers are required to bechanged when empty or after a predetermined period of time, such asthree months. To change the gas containers, the ion implanter needs tobe shut down, which adversely impacts fabrication time. In addition, asgas containers need to be replaced often (e.g., every three months), theprocessing cost for a gas supply system with gas containers can be high.Embodiments of the present disclosure, among other things, describe anapparatus, system, and method to provide a continuous gas supply with agas generator for one or more gases in the ion implanter. Though thefollowing embodiments are described in the context of an ion implanter,the embodiments can be used in other fabrication tools, which are withinthe scope and spirit of the present disclosure.

FIG. 1 is an isometric view of an IMP apparatus 100 with a gas supplysystem, according to some embodiments. IMP apparatus 100 can beconfigured to provide a desired doping type with a desired depth profileon a semiconductor wafer. IMP apparatus 100 can include a gas supplysystem 120, a source area 101, a beamline area 103, and a processchamber 105, where source area 101 can include a source head device 107and an atomic mass unit 108, where source head device 107 can beconfigured to generate and extract an ion beam 110 moving towards atomicmass unit 108 and beamline area 103.

Gas supply system 120 can provide gas sources to source head device 107through a gas line 109. Various gases can be provided by gas supplysystem 120, for example, boron trifluoride (BF₃), Arsine (AsH₃),germanium tetrafluoride (GeF₄), silicon tetrafluoride (SiF₄), nitrogen(N₂), oxygen (O₂), carbon dioxide (CO₂), hydrogen (H₂) or xenondihydride (XeH₂). In some embodiments, the gases can be provided by gascontainers and/or gas generators through gas line 109 at a certain flowrate controlled by multiple valves (not shown in FIG. 1 for simplicity).

Source head device 107 can include an ion source 102 and a bushing 104.Source head device 107 can further include conductor components couplingto ion source 102, where the conductor components can include metallicparts in source head device 107, such as a chamber 106. Ion source 102can be configured to generate an ion species by ionizing an implant gasor feed material. Ion source 102 can be further configured to extractthe ion species to generate ion beam 110 moving towards atomic mass unit108. Depending on the desired doping type on the targeted semiconductorwafer, different chemicals such as BF₃, AsH₃, GeF₄, or SiF₄, can beselected as the implant gas or feed material.

Atomic mass unit 108 can be disposed between source head device 107 andbeamline area 103. Atomic mass unit 108 can be configured to block afirst portion of ion species and allow a second portion of ion speciesin ion beam 110 to pass to beamline area 103. Atomic mass unit 108 caninclude a pre-position orifice and a magnet coil (not shown in FIG. 1)to generate a magnetic field, where the magnetic field can exert aspecific electromagnetic force for a respective ion species to flowthrough a corresponding circular path. Since a radius of thecorresponding circular path can be determined by a mass of therespective ion species, ion species having substantially the samekinetic energies but different masses can have different correspondingcircular paths. Therefore, a pre-position orifice can be disposed withinthe circular paths to selectively block the first portion of ion speciesand allow the second portion of ion species to pass to beamline area103.

Beamline area 103 can be disposed downstream of atomic mass unit 108 andcan be configured to accelerate, decelerate, deflect, scan, and shapethe filtered ion beam provided by atomic mass unit 108. Beamline area103 can include electrodes to accelerate or decelerate the filtered ionbeams to a different energy. Beamline area 103 can further include lens(not shown in FIG. 1) arranged to control dimensions of the filtered ionbeam in orthogonal directions to adjust a cross-section of the filteredion beam. Beamline area 103 can also include a scanning device (notshown in FIG. 1) to exert electric fields or magnetic fields to allowthe filtered ion beam to be scanned two-dimensionally on the targetedsemiconductor wafer. As a result, the filtered ion beam passing throughbeamline area 103 can be applied to irradiate on the targetsemiconductor wafer at process chamber 105.

In some embodiments, beamline area 103 can be a ballistic drift regionfor the filtered ion beams. In some embodiments, beamline area 103 canfurther include a bending magnet (not shown in FIG. 1) to filter neutralparticles in the filtered ion beam.

Process chamber 105 can include a holder (not shown in FIG. 1) to holdthe targeted semiconductor wafer. The holder can be configured to movethe semiconductor wafer two dimensionally relative to the ion beamprovided by beamline area 103. The holder can also be configured toallow a single semiconductor wafer to be irradiated by the ion beamserially at a time, or multiple semiconductor wafers simultaneously at atime by repeating a mechanical passage of the multiple semiconductorwafers through the irradiation of the ion beam.

FIG. 2 illustrates an exemplary gas supply system 120 with a clean gasgenerator for an ion implantation apparatus, according to someembodiments of the present disclosure. Gas supply system 120 includes agas container 201 with a gas container valve 203, a gas generator 205with a gas generator piping valve 207 and a water supply 204, gaspressure gauges 202 and 206, gate valves 211, 215, 217, and 221, massflow controllers (MFC) 213 and 219, gas lines 109, 209, 210, and 222,and a source head valve 223. Though a single gas container and a singlegas generator are shown in FIG. 2, based on the present disclosure,multiple gas containers and/or multiple gas generators can beimplemented. Such arrangements are within the spirit and scope of thepresent disclosure.

Gas container 201 can provide a gas, such as BF₃, AsH₃, GeF₄, SiF₄, N₂,O₂, CO₂, or XeH₂. Gas container valve 203 can control a flow of gas fromgas container 201. Gas container valve 203 can be a manually controlledvalve (or a computer controlled valve) and can remain open after gascontainer 201 is fluidly connected to gas line 209. Gas pressure gauge202 measures a gas pressure in gas container 201. Gate valve 217 cancontrol gas line 209 before the gas reaches mass flow controller 219.Mass flow controller 219 can limit or regulate the flow rate of the gasfrom gas container 201. Gate valve 221 can control the gas flowing fromgas line 209 to gas line 222. Closing of gate valve 221 can preventother gases in gas line 222 to flow to gas container 201 when the gas ingas container 201 is not in use. In some embodiments, mass flowcontroller 219 and gate valves 217 and 221 can be controlled by acontrol unit and can be opened and closed at the same time (or atdifferent times) when providing the gas from gas container 201.

In accordance with some embodiments of the present disclosure, gascontainer 201 can provide BF₃ to ion source head device 107. The flowrate of BF₃ can be in a range from 0 to about 5 cubic centimeter perminute. In some embodiments, the flow rate of BF₃ can be in a range, forexample, from about 0.5 to about 4 cubic centimeter per minute, about 1to about 3 cubic centimeter per minute, or about 1 to about 2.5 cubiccentimeter per minute. The flow rate of the gas from gas container 201is controlled by mass flow controller 219 and gate valves 217 and 221.After the BF₃ gas is ionized, boron ions from the ionized gas can beimplanted into certain regions of the semiconductor wafer. However,fluorine ions generated from ionization of the BF₃ gas can react withthe chamber metal from ion source head device to form a WF₆ byproduct,which could coat the semiconductor wafer and lead to degraded deviceperformance.

Referring to FIG. 2, gas generator 205 can generate one or more gasesfor gas supply system 120, such as H₂ or O₂, according to someembodiments of the present disclosure. The one or more gases can begenerated from an electrical source and a water source from water supply204. The generated gas can be controlled by gas generator piping valve207. The pressure of the generated gas from gas generator 205 can bemeasured by pressure gauge 206. Gate valve 211 can control gas line 210before the generated gas reaches mass flow controller 213. Mass flowcontroller 213 can limit or regulate the flow rate of the generated gasfrom gas generator 205. Gate valve 215 can control the generated gasflowing from gas line 210 to gas line 222. Closing of gate valve 215 canprevent other gases in gas line 222 to flow to gas generator 205 whenthe gas in gas generator 205 is not in use. Mass flow controller 213 andgate valves 211 and 215 can be controlled by a control unit, such as acomputer, and can be opened and closed at the same time (or at differenttimes) when providing the gas from gas generator 205.

In accordance with some embodiments of the present disclosure, gasgenerator 205 can generate clean gas H₂ from water supply 204 for ionsource head device 107. The flow rate of H₂ can be in a range from 0 toabout 5 cubic centimeter per minute. In some embodiments, the flow rateof H₂ can be in a range, for instance, from about 0.01 to about 1 cubiccentimeter per minute, about 0.05 to about 0.8 cubic centimeter perminute, or about 0.1 to about 0.5 cubic centimeter per minute. The flowrate of the generated gas from gas generator 205 is controlled by massflow controller 213 and gate valves 211 and 215. Generated H₂ can bemixed with BF₃ in gas line 222. The mixed gas can be provided to ionsource head device 107 for ionization, in which the ionized hydrogen canbe used to remove WF₆ byproduct through following chemical reactions:

BF₃→B⁺+BF⁺+BF²⁺+F⁺.

W+6F→WF₆.

BF₃+H₂+WF₆→W+B⁺+HF.

The generated W can be redeposited in ion source chamber instead ofcoating on the semiconductor wafer, thus removing WF₆ byproduct. Thegenerated hydrogen fluoride (HF) gas can be removed from the toolthrough an exhaust or vacuum system. And the ionized B⁺ can be implantedto the semiconductor device.

Gas generator 205 can also generate O₂ from water supply 204 for ionsource head device 107, in accordance with some embodiments of thepresent disclosure. The generated O₂ can be ionized for an. IMP process.In accordance with some embodiments of the present disclosure, anothergas generator can be fluidly connected to gas line 222 and can generateone or more other gases from an air supply. The one or more other gasesgenerated from the air supply can include N₂, O₂, CO₂, or other gases,in accordance with some embodiments of the present disclosure. Thegenerated N₂, O₂, or CO₂ gas can also be ionized for the IMP process.

In accordance with some embodiments of the present disclosure, the gasfrom gas container 201 and the generated gas from gas generator 205 canbe mixed in gas line 222 when mass flow controllers 213 and 219 and gatevalves 211, 215, 217, and 221 are open. The ratio of the gases from gascontainer 201 and gas generator 205 can be determined by the flow ratesof the gases, which are controlled by mass flow controller 213 and 219,respectively. In some embodiments, the ratio of the mixed gases from gascontainer 201 and gas generator 205 can be from about 1 to about 100,about 1.5 to about 50, or about 2 to about 25. The mixed gas can becontrolled by a source head valve 223 and provided to source head device107 through pipe line 109. Source head valve can be a manuallycontrolled valve (or a computer controlled valve) and can remain openduring the IMP process. In accordance with some other embodiments of thepresent disclosure, for another IMP process, gas line 222 can includegas from gas generator 205 and no gas from gas container 201.

In accordance with some embodiments of the present disclosure, sourcehead device 107 can maintain a pressure from about 1×10⁷ Torr to about1×10⁵ Torr. In some embodiments, source head device 107 can maintain apressure, for example, from about 5×10⁷ Torr to about 8×10⁶ Torr, about1×10⁶ Torr, or about 3×10⁶ Torr to about 5×10⁶ Torr. The pressures ingas container 201 and gas generator 205 can be higher than the pressurein source head device 107; so when valves 207, 211, 213, 215, and 223are open, the generated gas can flow from gas generator 205 to sourcehead device 107 through gas line 210 and 222. Similarly, when valves203, 217, 219, 221 and 223 are open, the gas can flow from gas container201 to source head device 107.

In accordance with some embodiments of the present disclosure, gascontainer 201 can be replaced after a predetermined period of time(e.g., about three months) or when gas container 201 is empty. IMPapparatus 100 may need to shut down during gas container replacement,which could reduce the IMP tool processing time. Gas generator 205 cancontinuously generate gas with continuous water supply. The generatedgas can be provided continuously until maintenance of gas generator 205after a predetermined period of time for maintenance (e.g., about twoyears). Gas generator 205 can reduce shutting down IMP apparatus 100 andthus improve IMP tool processing time. For example, gas supply system120 can supply gases by gas container 201 and gas generator 205.Compared to supplying gases with two gas containers, gas supply system120 can reduce about half of the gas container replacement time/toolshutting down time, as these two gas containers may not be changed atthe same time. In another example, gas supply system 120 can supply agas from gas generator 205 and no gas from gas container 201. In thiscase, there is no need for gas container replacement and/or the toolshutting down every three months. Maintenance of gas generator 205 isneeded, for example, about every two years. In addition, as gascontainers need to be replaced more often and the cost of gas containersis high, using gas generated from gas generators can reduce processingcost.

Gas supply system 120 can further include an emergency shutdown (notshown in FIG. 2). In some embodiments of the present disclosure, when agas leakage, power outage, power supply problem, or other emergencysituation occurs, the emergency shutdown can close all the valves in gassupply system 120 and shut down the IMP tool to prevent damaging thetool.

Gas supply system 120 can further include an inert gas supply and apurging system (not shown in FIG. 2). The inert gas can be argon,helium, or other inert gas. The purging system can purge the gas lineswith the inert gas during gas container replacement and/or gas generatormaintenance, thus preventing contamination in gas supply system duringthe replacement and/or maintenance processes.

FIG. 3 illustrates a gas generator 205 for gas supply system 120,according to some embodiments of the present disclosure. Gas generator205 can include water supply 204, an oxygen gas outlet 303, a hydrogengas outlet 305, an oxygen electrode 307, a proton exchange membrane(PEM) 309, a hydrogen electrode 311, and an electrical source 313. Gasgenerator 205 can use deionized (DI) water from water supply 204 andelectrical source 313 to generate oxygen and hydrogen gases for gassupply system 120.

In accordance with some embodiments of the present disclosure, gasgenerator 205 can use a platinum catalyst and PEM technology to splitthe DI water into oxygen and hydrogen ions. PEM 309 can allow water andpositive ions to cross between oxygen electrode 307 and hydrogenelectrode 311. PEM 309 can also serve as an electrolyte in gas generator205, instead of hazardous liquid electrolytes such as concentratedpotassium hydroxide. PEM water electrolysis can split DI water intooxygen that flows through oxygen gas outlet 303 and hydrogen that flowsthrough hydrogen gas outlet 305.

Electrical source 313 can be a direct current (DC) electrical sourceapplied to oxygen electrode 307 and hydrogen electrode 311. Oxygenelectrode 307 can be a positive electrode (or anode), and hydrogenelectrode 311 can be a negative electrode (or cathode). The DI waterfrom water supply 204 can be provided to oxygen electrode 307, in whichthe DI water is oxidized to oxygen gas and hydrogen ions (H⁺), whileelectrons (e⁻) are released through this chemical reaction:

2H₂O→4H⁺+4e ⁻+O₂.

The hydrogen ions can pass through PEM 309 to the hydrogen electrode,where the hydrogen ions can meet electrons from the cathode ofelectrical source 313 and reduce to hydrogen gas through this chemicalreaction:

4H⁺+4e ⁻→2H₂.

In accordance with some embodiments of the present disclosure, gasgenerator 205 can be a safe, convenient and cost-effective alternativeto high pressure gas containers. Gas generator 205 can produce gases ondemand at a regulated flow (e.g., 0.5 liter per minute) and pressure(e.g., 120 pound per square inch), as compared to gas containers storingup to thousands of liters (e.g., 9,000 liters) of gases at high pressure(e.g., 3,000 pound per square inch). High pressure compressed gas can betoxic, flammable, oxidizing, corrosive, and/or inert. In the event of aleak, large amount of gases can quickly displace air in a large area,creating poison atmospheres, fire and exploding gas containers, and/oran oxygen deficient atmosphere. Regulated gas flow and lower gaspressure of gas generator 205 can reduce these hazarders. Withcontinuous power supply from electrical source 313 and deionized watersupply from water supply 204, gas generator 205 can continuously providehydrogen and oxygen gases, thus resulting in less maintenance over time(e.g., about every two years) as compared to gases provided by gascontainers (e.g., about every three months).

FIG. 4 illustrates an exemplary method 400 for providing a mixed gas foran IMP apparatus, according to some embodiments of the presentdisclosure. This disclosure is not limited to this operationaldescription. It is to be appreciated that additional operations may beperformed. Moreover, not all operations may be needed to perform thedisclosure provided herein. Further, some of the operations may beperformed simultaneously, or in a different order than shown in FIG. 4.Operations of method 400 can be performed by, for example, gas supplysystem 120 of FIGS. 1-3. Operations of method 400 can also be performedby other embodiments discussed in this disclosure. In someimplementations, one or more other operations may be performed inaddition to or in place of the presently described operations.

At operation 410 of FIG. 4, a gas supply system can receive a watersupply for a gas generator. According to some embodiments of the presentdisclosure, the water supply can provide continuous deionized (DI) waterto the gas generator. Referring to FIG. 2, the DI water can be suppliedthrough water supply 204 to gas generator 205. According to some otherembodiments of the present disclosure, the gas supply system can alsoreceive an air supply for gas generator 205.

At operation 420 of FIG. 4, the gas generator can generate a first gasusing the water supply and an electrical source. According to someembodiments of the present disclosure, the gas generator can use PEMtechnology to split DI water into oxygen gas and hydrogen gas. Referringto FIG. 3, the first gas can be hydrogen and can be generated athydrogen electrode 311 of gas generator 205. According to some otherembodiments of the present disclosure, the gas generator can alsogenerate a first gas using an air supply.

At operation 430 of FIG. 4, the gas supply system can provide a secondgas from a gas container. According to some embodiments of the presentdisclosure, referring to FIG. 2, the second gas can be BF₃ and can beprovided from gas container 201 of gas supply system 120.

At operation 440 of FIG. 4, the gas supply system can control the flowrate of the first and second gases by respective gas flow controllers.According to some embodiments of the present disclosure, referring toFIG. 2, the flow rate of the first gas can be controlled by mass flowcontroller 213, and the flow rate of the second gas can be controlled bymass flow controller 219.

At operation 450 of FIG. 4, the gas supply system can mix the first gasand the second gas into a mixed gas. According to some embodiments ofthe present disclosure, referring to FIG. 2, the first gas from gasgenerator 205 and the second gas from gas container 201 can be mixed ingas line 222 into a mixed gas. The ratio between the first gas and thesecond gas in the mixed gas can be determined by their flow rate. Insome embodiments, the ratio of the mixed gases from gas container 201and gas generator 205 can be from about 1 to about 100, about 1.5 toabout 50, or about 2 to about 25.

At operation 460 of FIG. 4, the gas supply system can deliver the mixedgas through a gas pipe to an ion source head of an implantation tool.According to some embodiments of the present disclosure, referring toFIG. 2, the mixed gas can be delivered through gas pipe 109 to ionsource head device 107. The mixed gas can be ionized in source headdevice 107 and used for an IMP process and/or clean IMP byproducts.

In accordance with some embodiments of the present disclosure, anapparatus, system, and method are described to provide a continuous gassupply by a gas generator for one or more gases in an IMP system. Thegas generator can be a safe, convenient, and cost-effective alternativeto high pressure gas containers, and it can continuously provide gasesto the IMP system, thus resulting in less maintenance over time (e.g.,about every two years) as compared to gases provided by gas containers(e.g., about every three months). In addition, as gas containers need tobe replaced more often and the cost of gas containers is high, using gasgenerated from gas generators can reduce processing cost.

In some embodiments, a gas supply system includes a water supply, anelectrical source, a gas generator configured to generate a first gasfrom the water supply and the electrical source, a first flow controllerconfigured to control a first flow rate of the first gas, a gascontainer to provide a second gas, a second flow controller configuredto control a second flow rate of the second gas, and a gas pipeconfigured to mix the first and the second gas into a mixed gas.

In some embodiments, a method for providing a mixed gas to animplantation tool includes receiving a water supply, generating, by agas generator, a first gas using the water supply and an electricalsource, controlling the first gas by a first flow controller, providing,from a gas container, a second gas, controlling the second gas by asecond flow controller, mixing the first gas and the second gas into amixed gas, and delivering the mixed gas through a gas pipe to an ionsource head of the implantation tool.

In some embodiments, an ion implantation system includes an ion sourcehead configured to extract an ion beam, and a gas supply systemconfigured to provide a mixed gas to the ion source head, which includesa water supply, an electrical source, a gas generator configured togenerate a first gas from the water supply and the electrical source, afirst flow controller configured to control a first flow rate of thefirst gas, a gas container to provide a second gas, a second flowcontroller configured to control a second flow rate of the second gas,and a gas pipe configured to mix the first and the second gases into themixed gas and deliver the mixed gas to the ion source head.

It is to be appreciated that the Detailed Description section, and notthe Abstract of the Disclosure, is intended to be used to interpret theclaims. The Abstract of the Disclosure section may set forth one or morebut not all exemplary embodiments contemplated and thus, are notintended to be limiting to the subjoined claims.

The foregoing disclosure outlines features of several embodiments sothat those skilled in the art may better understand the aspects of thepresent disclosure. Those skilled in the art will appreciate that theymay readily use the present disclosure as a basis for designing ormodifying other processes and structures for carrying out the samepurposes and/or achieving the same advantages of the embodimentsintroduced herein. Those skilled in the art will also realize that suchequivalent constructions do not depart from the spirit and scope of thepresent disclosure, and that they may make various changes,substitutions, and alterations herein without departing from the spiritand scope of the subjoined claims.

What is claimed is:
 1. A system, comprising: a first flow controllerconfigured to control a first flow rate of a first gas provided by agenerator configured to continuously generate the first gas for a periodof time greater than that of a first gas container with a firstpredetermined storage capacity; a second flow controller configured tocontrol a second flow rate of a second gas provided by a second gascontainer with a second predetermined storage capacity; and a gas pipeconfigured to mix the first gas and the second gas into a mixed gas. 2.The system of claim 1, further comprising a plurality of valves tocontrol the first and second flow rates of the first and second gases,respectively, in the gas pipe.
 3. The system of claim 1, furthercomprising a gate valve connected to the first flow controller, anadditional gas pipe connected to the gate valve, a gas pressure gaugeconnected to the additional gas pipe, and a gas piping valve connectedto the generator to control the first flow rate of the first gas.
 4. Thesystem of claim 1, wherein the first gas comprises at least one ofhydrogen, oxygen, nitrogen, and carbon dioxide.
 5. The system of claim1, wherein the first gas is generated from a water supply provided bythe generator.
 6. The system of claim 1, wherein the first gas isgenerated from an air supply provided by the generator.
 7. The system ofclaim 1, further comprising another generator configured to continuouslygenerate a third gas for a period of time greater than that of a thirdgas container with a third predetermined storage capacity.
 8. A method,comprising: continuously generating, by a gas generator, a first gas fora period of time greater than that of a first gas container with a firstpredetermined storage capacity; controlling a first flow rate of thefirst gas by a first flow controller connected to the gas generatorthrough at least one valve; providing a second gas from a second gascontainer with a second predetermined storage capacity; controlling asecond flow rate of the second gas by a second flow controller; andmixing the first gas and the second gas into a mixed gas.
 9. The methodof claim 8, further comprising controlling the first and second flowrates of the first and second gases, respectively, in a gas pipe by aplurality of gate valves.
 10. The method of claim 8, further comprisingcontrolling the first flow rate of the first gas through a gate valveconnected to the first flow controller, a gas pipe connected to the gatevalve, a gas pressure gauge connected to the gas pipe, and a gas pipingvalve connected to the gas generator.
 11. The method of claim 8, furthercomprising delivering the mixed gas through a gas pipe to an ion sourcehead of an implantation tool.
 12. The method of claim 8, whereincontinuously generating the first gas comprises generating at least oneof hydrogen, oxygen, nitrogen, and carbon dioxide.
 13. The method ofclaim 8, wherein continuously generating the first gas comprisesgenerating the first gas from a water supply provided by the gasgenerator.
 14. The method of claim 8, wherein continuously generatingthe first gas comprises generating the first gas from an air supplyprovided by the gas generator.
 15. The method of claim 8, furthercomprising continuously generating, by another gas generator, a thirdgas for a period of time greater than that of a third gas container witha third predetermined storage capacity.
 16. An ion implantation system,comprising: an ion source head configured to extract an ion beam; and agas supply system configured to provide a mixed gas to the ion sourcehead, comprising: a first flow controller configured to control a firstflow rate of a first gas provided by a gas generator configured tocontinuously generate the first gas for a period of time greater thanthat of a first gas container with a first predetermined storagecapacity; a second flow controller configured to control a second flowrate of a second gas provided by a second gas container with a secondpredetermined storage capacity; and a gas pipe configured to: mix thefirst and the second gases into the mixed gas; and deliver the mixed gasto the ion source head.
 17. The ion implantation system of claim 16,further comprising a gate valve connected to the first flow controller,an additional gas pipe connected to the gate valve, a gas pressure gaugeconnected to the additional gas pipe, and a gas piping valve connectedto the gas generator to control the first flow rate of the first gas.18. The ion implantation system of claim 16, wherein the first gascomprises at least one of hydrogen, oxygen, nitrogen, and carbondioxide.
 19. The ion implantation system of claim 16, wherein the firstgas is generated from a water supply provided by the gas generator. 20.The ion implantation system of claim 16, wherein the first gas isgenerated from an air supply provided by the gas generator.